Take out the existing floor register and measure the length width of the opening in inches all registers will be listed in inches.
Proper size floor registers.
How to measure floor registers and grilles.
Find large and over sized floor registers and floor return grilles in multiple styles and finishes.
The duct vent size will depend on the size of the furnace and the size of your home so you know how many vents you need in each room.
The furnace s british thermal units btus will help calculate the size it needs.
The register shown above is a common aluminum adjustable curved blade one way 10 6 ceiling register.
In order for your forced air furnace to work properly you have to have the right sizes of duct vents in each room expelling air.
Registers have the same inlet neck and outlet face size.
Registers are the most common type of supply vent.